This dude’s name is Cicero and he is an “inkeater.” Inkeaters are essentially weird spirits that feed off of unfinished or forgotten artwork. They come in a remarkable variety, but all possess a long tail with three bobbles of ink and generally have neutral/earthy colouration (most commonly: black, grey, silver, and white.)
When healthy and happy, the largest bobble is colourful and bright with a pulsating array of colour. When sick or upset, the colours in the largest bobble become murky and dark. Without the consumption of artwork, inkeaters dry up and, eventually, perish.